Please confirm topic selection

Are you sure you want to trigger topic in your Anconeus AI algorithm?

Please confirm action

You are done for today with this topic.

Would you like to start learning session with this topic items scheduled for future?

Updated: Feb 15 2020

Legionella pneumophila

  • Snapshot
    • A 60-year-old man is brought to the emergency department for confusion, cough, and diarrhea. He had recently attended a conference and stayed at an old hotel where other people reported similar symptoms. His past medical history includes chronic obstructive pulmonary disease and hypertension. He smokes 1 pack per day. On physical exam, his oxygen saturation is 92% on room air. There are fine crackles bilaterally on chest auscultation. A chest radiograph reveals diffuse patchy infiltrates. He is also found to have hyponatremia. A urine antigen test was sent for definitive diagnosis.
  • Introduction
    • Classification
      • Legionella pneumophila
        • an aerobic, facultative, intracellular gram - rod
      • transmission
        • aspiration of contaminated water/soil
          • air conditioning
          • hot tubs
          • swimming pools
    • Epidemiology
      • demographics
        • more common in the elderly
      • risk factors
        • cruise ships
        • smoking
        • immunosuppression
        • hospitalization
    • Pathogenesis
      • organism is phagocytosed into alveolar macrophages, where they replicate
      • bacterial spread occurs when they escape from macrophage vacuoles leading to host cell osmotic lysis
    • Associated conditions
      • Legionnaires disease (most common)
        • lobar or insterstitial pneumonia
        • gastrointestinal and central nervous system involvement
        • more common in smokers and those with chronic lung diseases
      • Pontiac fever
        • mild and flu-like without significant pulmonary involvement
    • Prognosis
      • Pontiac fever is self-limited
  • Presentation
    • Symptoms
      • Legionnaires disease
        • cough with sputum production
        • gastrointestinal symptoms
          • nausea or vomiting
          • water diarrhea
        • central nervous system symptoms
          • confusion
          • encephalopathy
      • Pontiac fever
        • malaise
        • headache
        • malaise
    • Physical exam
      • fever
      • Legionnaires disease
        • altered mental status
        • dyspnea
        • relative bradycardia
        • pneumonia
  • Imaging
    • Chest radiography
      • indication
        • all patients
      • findings
        • lobar consolidation or
        • diffuse patchy infiltrates
  • Studies
    • Labs
      • urine antigen test
        • diagnostic
      • does not Gram stain well, so it requires a silver stain
      • sputum culture
        • requires special media for culture
        • charcoal yeast extract agar buffered with iron and cysteine
      • hyponatremia
      • transaminitis
    • Making the diagnosis
      • based on clinical presentation and laboratory studies
  • Differential
    • Mycoplasma pneumoniae
      • distinguishing factor
        • typically does not present with gastrointestinal or central nervous system involvement
  • Treatment
    • Medical
      • antibiotics
        • indication
          • all patients
        • drugs
          • macrolides
          • respiratory fluoroquinolones (levofloxacin and moxifloxacin)
  • Complications
    • Respiratory failure
1 of 0
1 of 4
Private Note

Attach Treatment Poll
Treatment poll is required to gain more useful feedback from members.
Please enter Question Text
Please enter at least 2 unique options
Please enter at least 2 unique options
Please enter at least 2 unique options